Heterobimetallic complexes containing ferrocene and late transition metal complexes with nitrogen ligands form different geometrical isomers, with distinct electrochemical features and antiproliferative activity.

Bis(2-picolyl)amine (bpa), iminodiacetamide (imda), and bis-1,2,3-triazole (bta) ferrocene ligands (L) with and without an aliphatic linker were prepared by multi-step synthesis. The cis-fac, trans-fac, or mer stereochemistry of their ML₂ complexes with Ni(II), Cu(II), Cd(II), and Zn(II) was studied in the solid state (infrared [IR] and single-crystal X-ray diffraction [SC-XRD]), in solution (nuclear magnetic resonance [NMR] and cyclic voltammetry [CV]) and by density functional theory (DFT) calculations. Crystal structures were determined for bpa ligand 7, and complexes [Ni(1)₂](NO₃)₂ (1 _Ni ), [Cu(8)₂]OTf₂ (8 _Cu ), [Ni(10b)₂](NO₃)₂ (10b _Ni ), and [Cu(10b)₂]OTf₂ (10b _Cu ). The bond strength of the central metal ion to the ligand amine nitrogen atom was studied by NMR, electrochemistry, and DFT. The information on redox-active centers, electron transfer properties of ferrocene ligands (L), and their in situ complexation with zinc(II) and nickel(II) ions were obtained by voltammetric analysis. In addition, DFT calculations showed that the electron ionization in ML₂ complexes occurs from one of the ferrocene units, leaving the electronic structure of the other ligand intact, while some of the expelled electron density is recovered by the adjacent amine through resonance. This effect is more pronounced in the free ligands, because the eventual amine resonance in ML₂ needs to balance its Zn(II) coordination participation, which justifies why they show higher ionization energies over free ligands. Moreover, due to lower steric hindrance, the N(amino)–Zn(II) coordination is additionally stronger in 1:1 ML complexes, which makes their electron depletion further more demanding. If compared with the clinical drug cisplatin, complexes of bpa 1 _Ni and imda 2 _Ni showed a better effect on the viability of different tumor cell lines and better selectivity towards normal cells. Treatment with 1 _Ni and 2 _Ni causes an increase of cells in the S phase of the cell cycle and leads to the accumulation of cells in G₀/G₁. A decrease in the expression level of anti-apoptotic marker Bcl-2 upon treatment with both compounds together with increased amount of Annexin V-FITC positive cells implied apoptosis as the mode of cell death.

The non-covalent index technique provides important evidence of different forces like H-bonding, van der Walls, and steric interaction. The RDG plot shows that the interaction increases and stabilized through either H-bond or steric interaction (more prominent and more scatter points). The most interaction and stability was for Co(II) complex.

This work aimed to create and characterize some new bioactive chelates of bis azodye ligand, 5-((2-hydroxy-4,6-dioxo-1,4,5,6-tetrahydropyrimidin-5-yl)diazenyl)naphthalen-1-yl)diazenyl) pyrimidine 2,4,6 (1H,3H,5H)-trione. Except for the Sm(III) chelate, which exhibited a (3M:1L) molar ratio, all chelates had a (2M:1L) stoichiometry. According to Fourier transform infrared spectroscopy (FT-IR), azo groups were not included in chelating with all ions except Sm(III), where just one azo group was coordinated. With the Ni(II) and Zn(II) ions, the ligand behaved as OON-tridentate moiety; with the Co(II) and Cu(II) ions, it behaved as ON-bidentate moiety. Co(II) and Cu(II) chelates had square planar structure, and Ni(II) and Zn(II) chelates had square pyramidal geometry. The chelates had greater thermal stability than the uncoordinated ligand due to the chelate's structure. [Sm₃(H₄L)(OH)₇(NO₃)₂.H₂O].4.5EtOH exhibited the maximum thermal stability, which may be due to the large number of solvent molecules and the high number of chelate rings. With the exception of the Sm(III) chelate, all of the examined chelates were more cytotoxic against MCF-7 and Hep-G2 cells than their parent ligand. With the exception of the Zn(II) chelate, which demonstrated activity on Hep-G2 rather than MCF-7, the effects of each metal chelate on the two cells were nearly equivalent. All of the studied chelates, especially Zn(II) and Co(II), were potent as antioxidants more than the native ligand. To support experimental findings, density functional theory (DFT) studies were performed via the CAM-B3LYP/LanL2DZ method, and the geometry of the ligand and its chelates had been validated.

Figure 1 Illustration of oxygen vacancy-enhanced active sites of Pt_0.7-Ce_0.5/TS-1.

We constructed a series of Pt-based titanium-silicalite-1 (TS-1) bifunctional catalysts modified with Ce through a simple spin-coating impregnation method. Under the enhancement of oxygen vacancies, Pt_0.7-Ce_0.5/TS-1 exhibited excellent aqueous phase hydrogenation performance (with an LA conversion rate of 99.8% and GVL selectivity of 99.6%).

The selective conversion of levulinic acid (LA) obtained from lignocellulosic biomass represents a crucial pathway for producing the key value-added chemical compound γ-valerolactone (GVL). Herein, we constructed a series of Pt-based titanium-silicalite-1 (TS-1) bifunctional catalysts modified with rare earth metal Ce through a simple spin-coating impregnation method, and the catalytic performance was significantly improved compared to the unmodified Pt_1.2/TS-1. Pt_0.7-Ce_0.5/TS-1 exhibited the best aqueous-phase catalytic activity (with a GVL yield of 99.4%). The introduction of CeO_x can reduce the particle size of Pt nanoparticles and promote the formation of electron-rich Pt species while delivering abundant oxygen vacancies (O_V) for the catalysts. The characterization and testing results highlight the synergistic effect of O_V and electron-rich Pt sites on the oriented adsorption and selective hydrogenation of LA, providing new insights into constructing more efficient noble metal-based zeolite catalysts for biomass conversion.